Fiber treating machine



Aug. 10, 1954 A. R. BLACK FIBER TREATING MACHINE 5 Sheets-Sheet 1 Filed April 3, 1950 Aug. 10, 1954 A. R. BLACK 2,685,826

FIBER TREATING MACHINE Filed April 3, 1950 5 Sheets-Sheet 2 ,mllllml' Q 'Byfli/zgjlNzENToR.

Aug. 10, 1954 A. R. BLACK 2,685,826

FIBER TREATING MACHINE Filed April 5, 1950 5 Sheets-Sheet 3 2f [/2 if 5 T1E 4.

INVENTOR. Y Z

g- 10, 1954 A. R. BLACK 2,685,826

FIBER TREATING MACHINE Filed April 5, 1950 5 Sheets-Sheet 4 0, 1954 A. R. BLACK 2,685,826

FIBER TREATING MACHINE Filed April 5, 1950 5 Sheets-Sheet 5 INVNTOR. a

Patented Aug. 10, 1954 UNITED STATES PATENT OFFICE FIBER TREATING MACHINE Andrew R. Black, Fulton, N. Y.

A p ati April Se ial N 153 59 Claims.

My present invention comprises a novel construction of a machine for the treatment of fiber to be used in the art of paper making.

A machine built in accordance with my inven tion is designed primarily for breaking up prepared material such a chemical pulp, ground Wood, or rag fiber, in a suitable amount of water which enables the pumping and circulating of the material to and from a novel type of crushing or grinding unit for reducing or pulping the material or fibers to cause the latter to become individually suspended in the water. The grinding or pulping unit referred to is of a peculiar construction for effecting the cutting and beating of the fibers to any desired condition and in the operation of my machine chemicals may be mixed uniformly with the fiber and fibers and water and the mixture circulated without further mechanical change in the fiber condition according to predetermined requirements.

A special feature of importance in the improvements of my machine as heretofore referred to lies in the construction of the grinding or crushing unit by which the fibers are treated, the said unit being associated with the tank or vat in which the material to be treated is disposed and from and to which the said materials are circulated after being passed through the grinding or crushing unit. The said unit in respect to its novel phases of construction comprises primarily a shell equipped with fixed or stationary grinding or crushing bars or blades disposed in a circular arrangement and which blades are spaced apart to permit the passing of the material being treated therebetween. Associated with the said stationary or fixed bars of said unit I provide a rotor comprising a driving shaft actuating means and opposite heads which support the rotary grinding blades or bars arranged to coact with the previously mentioned fixed bars of the shell, the rotor supported bars or blades being designed to be driven at high velocity by any suitable driving motor connected to the men tioned shaft, and said latter blades being also spaced apart so that the material being treated may pass between the rotating blades or bars in a direction of outward flow between the stationary blades or bars so that by the cooperation of the rotating and stationary bars the fiber material circulated with the water containing the same may be reduced to such extent as may be desired or req ed n referen e o h breaking up or tearing of the material or fibers.

'By eason of the sp cia c ns ruetieh o my crush n nd r n in unit, melodies cert n ad- 1 2 lusting mechanism for varying the position of the rotor carrying the rotating bars, in relation to the fixed bars which surround the rotor, the machine may be operated to control readily the degree of crushing or reduction to pulpous condition of the material being treated.

In the operation of my improved machine, furthermore, it is notable that the rotor referred to comprises a propeller for efifecting the circulation of t mate ial to e. r a ed o c ry sa d aterial from the tank or vat in which it is originally received through the grinding and crushing unit, and particularly through the circularly arranged spaced rotating bars, and stationary bars of said unit, ack o the ta k or a t e ci u tion to be kept up as long as necessary to bring t aterial to he final ee diti n t e b in in t eatm by the machine of e nve n. o eo r in t e i cu at o er io ust described, it is contemplated as a special feature of advant e us action o m mac ine t a the rotor may be periodically adjusted to gradually reduce or crush t fib ous ma eri l o its u mate cond tion i re t c c e f th c rc let n pe ati n su a le m n l p vi n being made for fiecting the adjustment of the rotor with its high speed acting rotating bars or blades while said rotor is in operation to coact with the fixed or stationary blades surrounding the rotating blades, in the treatment operation.

My invention involves certain other detail features of construction of the machine generally outlined above in regard to its novel phases of construction, and the objectives of my invention, and the manner of carrying out the same Will be more clearly understood upon reference to the following detail description, and to the accompanying drawings.

In the annexed drawings:

Figure l is a general perspective view of a ma chine embodying the essential features of my invention. The arrows associated with the tank or vat, and the grinding or crushing unit, indicate the direction of flow of the liquid suspended material from the tank to the grinding or crushing unit and from the latter back to the tank.

Figure 2 is a top plan view of the machine of the invention.

Figure 3 is a vertical longitudinal section through the machine, the grinding or crushing unit being illustrated partly in elevation and partly in section.

F ur e s an nla ed f a mentary sect na1 view showin more c earl h de ai nst uctier; o th eriiehihe and grindin u i Figure 5 is a cross sectional view, taken about on the line 5-5 of Figure 4.

Figure 6 is a detail view in elevation showing more clearly the construction of the propeller forming a part of the rotor.

Figure '7 is a detailed sectional view, taken about on the line '!--1 of Figure 6.

Figure 8 is a fragmentary view bringing out more clearly the mounting of the motor driving means for the rotor and the connection of the motor with the rotor shaft; also the adjusting devices employed for moving the rotor axially to vary the clearance between its rotating blades and the fixed or stationary blades of the surrounding shell.

Figure 9 is a detail view bringing out more clearly the adjustable thrust bearing utilized to connect the rotor shaft with the manual adjusting means for the rotor.

Figure 10 is a detail view of certain of the shaft parts operated by the manual adjusting handle for the rotor.

Figure 11 is a fragmentary somewhat diagrammatic view showing generally a preliminary adjustment positioning of the rotor blades relative to the stationary blades or bars for initial treatment of the material.

Figure 12 is a view somewhat similar to Figure 11, showing a further illustration of the manher of positioning the rotor blades in relation to the stationary blades with less clearance than provided in the illustration of Figure 11, to bring about a further reduction or crushing of the treated material.

Figure 13 is a detail somewhat diagrammatic View showing the general machine of the invention, omitting the motor driving features and bringing out more clearly the manner of introduction of the material to be treated, into the vat or tank from and to which the said material is circulated when passing through the grinding or crushing unit.

Referring to the annexed drawings, the construction of my machine will be seen to comprise primarily a tank A which is of general circular form preferably, and partially covered by a cover B. Within the tank A are mounted curved baffles I which are spaced apart and each of which is spaced from an adjacent portion of the circular wall of the tank, at the outer side of the baiile. The baffles l are spaced apart also at one end to provide communication between the outer flow channel, designated 2 in the drawings, at the outer side of one bafile and the outer flow channel 3 at the outer side of the other bafiie, and

what may be characterized as the inner flow channel 4 located at the middle of the tank A and between the two baiiles l The bafiies l at the ends thereof, opposite the spaced ends above referred to, lead to and are connected with a suitable plate 5 forming a vertical partition in the tank A located adjacent to the crushing and grinding unit which is gen- 4 point 9 thereof in opposite directions, to the wall of the tank.

The outflow pipe 6 will be equipped with a common type of control valve which may be opened in order to permit the passing out of the tank A of the material therein after the treatment process obtained in the operation of the machine of this invention.

Referring now to Figures 4 and 5 of the drawings primarily, the construction of the grinding and crushing unit of this invention will be set forth. Said unit comprises an outer shell it} having an inner end member or head ll in contact with the plate or partition member 5 previously referred to as being joined to the baffles l. The members 5 and I l have cut out portions to provide an intake opening leading into the space surrounded by the shell It from the inflow channel 4 between the baflies l. The shell in is equipped also with an outer head or end member 12 which is formed with an opening axially aligned with the opening in the head I l but con-- siderably larger. At the opening portions of the heads I l and I2 of the shell 19 are provided series of spaced radially extending slots and in these slots are disposed the ends of a series of fixed blades or bars i3, rigidly held in place in said slots and maintained in their positions in any suitable manner. Because the openings in the heads I! and i2 are of different diameters, the attachment of the blades or bars I3 is nec essarily such as to dispose these bars at an angle to the axis of the openings in the said head. The fixed or stationary bars l3 are spaced apart predetermined distance and, of course, are disposed in a circular arrangement which is quite evident upon reference to Figure 5 of the drawmgs.

Within the space surounded by the circularly disposed bars 13 is arranged the main structure of the rotor of the present invention, which rotor comprises a central driving shaft I l, an outer disc-like head i5, and an inner propeller wheel I6, the spokes ll of which are disposed at a suitable angle to provide propeller blades, see Figure '7. The wheel or propeller It may be an integral cast portion of the disc-like head l5 of the rotor and it is notable that the inner surface of the head 45 is curved from the outer periphery of said head toward the hub portion [8 and in the direction of the propeller wheel 16. The purpose of this formation of the head i5 is to cause the flow of the treatment material passing to the rotor through the central openings of the parts 5 and ii, and through the propeller E6, in a direction radially and outwardly toward the shell wall it, said wall having suitable openings at opposite sides thereof to enable the material to pass out from the shell and back to the tank A and to the outflow channels 2 and 3 of said tank, previously referred to.

The rotor now being described carries a series of grinding or crushing bars or blades 59 of a generally similar construction to the blades 53, blades 19 being arranged parallel to the blades 3 by reason of the fact that the outer perimeter oi the head 15 is of much greater diameter than the corresponding perimeter of the propeller wheel l6. In the rim portion of the disc head l5 are provided a series of circumferentially spaced radial slots adapted to receive the adjacent ends or outer ends of the blades l9. In like manner, the rim of the propeller wheel I6 is formed with circumferentially spaced and radially extending slots for receiving the other ends of the blades or bars i 9'. Attached to the rim of the'head 15 is 'a retainer ring'Et held in place by screw bolts 2! which retainer ring overlaps the outer edges of the adjacent ends of the blades l9 and maintains such ends of the blades firmly seated on the head 15. In like manner, onthe rim portion. of the propeller wheel it there is provided a retainer ring 22, held in place by screw bolts 23, and this retainer ring 22 overlies the adjacent ends of the blades or bars i 9 whereby to hold the same firmly in connection with the inner end of the rotor provided by the propeller l6. Detachment of the retainer rings 29 and 22 enables replacement of the bars 89 after they have become worn under actual conditions of use in my machine.

The driving shaft M by which the rotor is rotated at high velocity is secured to the hub portion 18 of the head i and wheel 56 by means of a detachable screw head 24 adapted to be screwed onto the screw threads 25- on the inner end of the shaft M. The head 24 is a breaker head in that it is equipped with a series of radially disposed breaker arms 26 at spaced intervals outwardly of the head, said breaker arms 26 being located some in parallel and others in rectilinear relation, and being used for the purpose to be set forth hereinafter.

The shaft M is of enlarged diameter, as shown at Ma, outwardly of the spindle portion that is connected directly with the head l5 and propeller wheel i6, and the said enlarged portion is shown in Figure 4 as passing through the packing gland 2?. The gland 27 is carried by an outer closing plate 23 which is attached to an extension of the shell id located outwardly of the end member, l2, of said shell and the ring 2!) is housed in the space between the parts l2 and 28, seen best in Figure 4.

Now having in mind the construction and arrangement of the rotor carrying the rotating blades or bars for cooperation with the stationary blades or bars 53, I now describe certain adjusting means for imparting slight longitudinal movement to the shaft [4 for varying the spacing or amount of clearance between the blades l3 and the blades [9. Reference is made to Figures 8 to of the drawing in the above connection. As seen in Figure 8, I provide a shaft 39 rotatable by hand wheel 3!, the shaft 39 being in bevel gear connection with a shaft 32 disposed parallel with the shaft M. The shaft 32 is equipped with a screw thread and is mounted to rotate in a suitable supporting bracket 33 adjacent to the shaf id and between pillow-block bearing supports St for said shaft E i. On the shaft is, intermediate the bearing supports 34, I provide a thrust bearing unit seen best in Figure 9 and designated generally D. This bearing unit encloses a collar 35 which is fixed to the shaft is by an interlocking connection designated 36. The thrust bearing unit D is virtually a housing unit with ball bearing means intermediate the inner end walls of the unit and the collar 35, said bearing means being designated 31. An arm 38 offstands from the outer end of the thrust bearing D and has a threaded opening through which the screw shaft 32 passes. From the foregoing it is obvious that when the hand wheel 3| is turned in one direction to turn the shaft 32 the bearing D may be moved toward the unit C for reducing the clearance between the blades [3 and I9, and when the wheel 3i is manually operated in a reverse direction the shaft It may be shifted slightly outwardly and thereby increase the 6? clearance between thev blades l3'and H3 in a. selfcvident manner.

For the driving of the shaft l4 any suitable motor means may be employed. As illustrated in the drawings, an electric motor E is mounted upon a housing 39 attached to the tank A adjacent to the unit C and said motor E is connected by suitable V-belts 40 to a pulley wheel 4! attached fixedly to the outer end of the shaft Hi, the belts being also passed about a pulley wheel 42 on the motor shaft.

Figures 1 and 3 show the openings :33, one of which is provided in each of the sides of the shell l0 horizontally radially to the rotor blades, through which openings the treatment liquid passes from the rotor unit and shell or casing it back to the channels 2 and 3 which have been called herein the outflow channels of the tank leading from the grinding and crushing unit.

With the foregoing construction of my invention set forth the operation of the same will now be outlined.

The tank A is filled to a nearly full condition, with water, the surface of the water being a few inches below the top of the tank. The material to be mixed or treated in the machine is placed in the tank about at the location indicated by the arrow 3: shown in Figure 13. It will be assumed that the material is paper stock and it is therefore placed in the water in the tank, as noted above, to be circulated from the tank through the grinding and crushing means and back to the tank for recirculation. During the initial operation of the machine the rotor carried bars l9 are adjusted by the operation of the manual wheel 3| effecting movement of the shaft l4 so as to provide for maximum clearance between the said blades l9 and the blades 13 fixed in relation thereto. The rotor unit is then started into operation by being driven from the motor E, the material in the form of sheets or laps being fed into the tank at a uniform suitable rate. The propeller wheel it being, of course, driven by the shaft [4 due to the fact that said Wheel is a part of the rotor causes the flow of the water carrying the material to be treated into the crushing and grinding unit at the lefthand end of the so-called inflow channel s. The said material is first acted upon by the breaker arms 26 which are rotating at high velocity simultaneously with the rotation of the blades l9 and the action of said arms is to reduce the material to pieces small enough to pass through the propeller Wheel H5 at the spaces between the spokes ll of the latter, whereupon the material in such small pieces is carried into the space surrounded by the rotor blades is and the fixed blades or bars l3. In this operation the propeller wheel It acts virtually as a centrifugal pump and when the material reaches the space within the rotor blades I9 it is thrown by centrifugal force and the directing action of curvature of the inner surface of the head I 5 of the rotor into the spaces between the rotating bars or blades it which drive it at high velocity against the edges of the fixed bars or blades 43 and break it up into still smaller pieces.

The material continues on through the spaces between the fixed bars l3 and into the outer channels 2 and 3 of the tank from whence it is deflected by the opposite sides of the deflector 8 to enter the inflow channel d of the tank and continue on and back to the unit C again for "operation thereon by the rotor blades I9 and the fixed blades or bars I3. This circulating action of the material is repeated with sufficient cycles to bring the material to the pulped condition desired.

The action of the bars I3 and I9 on the material is illustrated fairly clearly in Figures 11 and 12 of the drawings, which are diagrammatic figures and which show the material in pieces as it is being reduced in size and separated into smaller parts in the zone of action of the blades I3 and I9 working together and carrying the material through the spaces between such blades back to the channels 2 and 3 of the tank.

In Figure 12 there is illustrated the further action of the machine in additionally reducing the material to its pulpous condition of separating the fibers from themselves, the clearance between the blades I3 and I9, as represented by the dash-dot lines, being greatly reduced because the material has been previously reduced to very small bundles of fibers and the close clearance is required for the bars !3 and I9 to now act upon the previously reduced parts of the material. Figure 12 shows the way in which the fibers are collected and torn to pieces and pulled apart.

It will be understood, of course, that the wheel BI is manually adjusted to obtain the clearance between the blades, as illustrated in Figure 12, after the operation of treatment has been conducted incident to the disposition of the blades with the greater clearance illustrated in Figure 11.

After the operation illustrated or depicted in Figure 12, the manual wheel 3i may be operated to obtain a finer or closer clearance of the bars or blades i3 and i9 and the fibers will then be beaten and split and frayed and brushed to further reduce them to the required pulpous condition that may be desired. The said clearance between the bars I3 and i9 may be further reduced so as to correspondingly additionally work the fibers to the condition of their ultimate use.

My machine may be employed for mixin dissimilar materials by utilizing the circulation flow action of the said materials in the tank A, the materials being blended by flowing to the inflow channel 4, between the baffles I, carried through the crushing and grinding unit into the rotor at which both materials to be blended Will be received in approximately a uniform ratio. By said rotor unit and its operation the materials are mixed by being rotated together and pumped out into the outflow channels 2 and 3 for further circulation as may be necessary to complete the blending.

Upon reference to Figure 3, it is noted that deflector plates 45 are located near the end of the bafiles I adjacent to the unit C, which plates tend to deflect the material being processed toward the center of the opening in the partition 5 adjacent to the propeller or pumping wheel I6, thus to concentrate the movement of the material more readily towards the central space surrounded by the rotating blades or bars I9 of the rotor unit.

'The peripheral speed of the rotating bars I9, in the operation of the rotor at high velocity, being many times greater than the speed of flow of the material which is being treated and which passes through and between the said bars, as well as through and between the bars 13, affords an exceedingly advantageous efficiency of the treatment operation by causing the material to be beaten, sheared, or brushed, as desired, in many consecutive strokes as the bars cut or strike through such material. In other words, as the material moves outward through the rotating bars it is carried across the bases of the fixed bars to be sheared into many thin sections. This results in every fiber that passes through the working elements [3 and I9 receiving the same degree of treatment since all of the material must pass through the rotor in its cycle around the tank and back to the rotor, the material will receive equal and uniform treatment throughout its mass. The action stated is far more effective on the material than is incident to those types of machines wherein coacting rotating bars or blades and stationary blades are used but in which the material largely is carried along the blades and their coacting surfaces in a direction longitudinal to, or parallel with the blades.

When the treatment or processing of the material has been completed the same will be discharged through the center opening of the tank A and the pipe or conduit 6 to a tank or pump located below, and the opening at the pipe 6 is controlled by a standard paper stock quick opening valve, the handle of which is extended under the tank bottom to the outside of the tank.

Water with which to fill the tank A will be supplied by a pipeline directly terminating above the tank and controlled by suitabl hand operated valve. The last described features, being conventional in the art, are not shown in the drawings.

While the specific details of construction have been herein shown and described, the invention is not confined thereto as changes and alterations may be made without departing from the spirit thereof as defined by the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a machine for treating paper stock, in combination, a tank for receiving material to be treated, and a crushing and grinding unit comprising a shell chamber having an inflow communicating With the tank, outer spaced reducing bars fixed in said chamber, a rotatable shaft extending into said chamber, a rotor mounted on said shaft within said fixed reducing bars and comprising spaced rotatable reducing bars coacting with adjacent portions of the fixed bars, said rotor including a propeller fixed to said shaft for circulating a liquid mass from the tank into the rotor and through the spaces between the rotatable and fixed reducing bars back into the tank, said rotatable reducing bars being supported at one end by said propeller and at their other end by a portion of said rotor spaced from said ropeller, and power means to drive the shaft and rotor at high velocity.

2. A machine as claimed in claim 1, in which the rotor includes spaced end heads, one adjacent the tank comprising the propeller aforesaid and having an inflow opening therethrough, the other remote from the tank and formed with a deflecting surface to direct the treated material entering the rotor radially of the latter to pass through the spaces between the rotor bars and fixed bars.

3. A machine as claimed in claim 1, in which the rotor includes spaced end heads, one adjacent the tank comprising the propeller aforesaid and having an inflow opening therethrough, the other remote from the tank and formed with a deflecting surface to direct the treated material entering the rotor radially of the latter to pass through the spaces between the rotor bars and the fixed bars, the propeller androtor forming a unitary assembly" and being disposed at the inflow to the shell chamber.

4. A reducing unit for treating paper stock comprising a shell chamber circularly arranged spaced fixed reducing bars in said chamber, a rotor shaft extending intosaid chamber, a rotor assembly on said shaft rotatably mounted in said shell chamber including circularly arranged rotative reducing bars concentric within and having working faces coacting with those of the fixed bars, said rotor assembly also including a propeller fixed to said shaft for moving a liquid mass into the space surrounded by the rotating bars and radially through the spaces between the fixed and rotative bars during working interaction of the latter, said rotative reducing bars being supported at one end by said propeller and at their opposite end by a portion of said rotor assembly spaced from said propeller, and power means to rotate the rotor assembly at relatively high velocity.

5. A machine as claimed in claim 4, in which the propeller comprises spaced spoke blades and an annular rim about the outer extremities of said spoke blades, said rotating bars being supported at one end by said propeller rim, and a breaker head fixed to the propeller at one side of the same and including breaker arms to initially break up paper stock before the propeller acts thereon.

6. In a machine for treating paper stock, in combination, a tank for receiving material to be treated, a shell having an inflow opening communicating with the tank, said shell being fixedly mounted with respect to said tank and having outer circumferentially spaced reducing bars fixed thereto, a removable unit comprising a rotor mounted within said fixed reducing bars, said rotor having circumferentially spaced reducing bars carried thereby for coaction with the fixed reducing bars aforesaid, a rotatable shaft on which said motor is mounted, supporting means for said shaft, driving means for said shaft carried by said supporting means, said supporting means including a closure plate for closing one side of said shell, said closure plate being removably secured to said shell and securing said removable unit in operative relation to said shell, and outlet means leading from said shell into said tank.

7. In a machine for treating paper stock, in combination, a tank for receiving material to be treated, a shell having inflow and outflow openings communicating with the tank, said shell being fixedly mounted with respect to said tank and having outer circumferentially spaced reducing bars fixed thereto, said outer bars diverging away from said inflow opening, a plate removably mounted on said shell and forming a closure for the same, a rotatable shaft journalled in said plate and having an end projecting through said plate and within said outer bars, a rotor member mounted on the aforesaid end of said shaft, said rotor membe including inner circumferentially spaced reducing bars carried thereby, said rotor bars diverging towards said plate at an angle corresponding to the angle of divergence of the outer bars aforesaid and being disposed in coacting stock-treating relation to said outer bars, supporting means on said plate on the opposite side thereof from said rotor, power means carried by said supportin means and operatively connected with said shaft for driving th shaft and rotor at a relatively high speed, and removable means removably securing said plate to said 10 shell, said plate, shaft, rotor, supporting means and power means constituting a unit which is removable from said tank and from said shell for allowing service of said rotor bars and said outer bars upon removing said removable means.

8. A reducing unit for treating paper stock, comprising a shell forming a treatment chamber, circularly arranged and spaced outer reducing bars carried by said shell, a rotor rotatably supported in said chamber and having circularly arranged and spaced inner reducing bars concentrically disposed within said outer reducing bars, said outer and inner bars respectively having working faces adapted to coact with one another on rotation of said rotor, a circular support on each end of said rotor, each of said circular supports having radially disposed recesses therein, said inner reducing bars each being seated at its opposite end in a recess in the respective circular supports, a locking ring disposed about at least one of said circular supports and overlying the recesses therein and retaining the respective ends of said inner bars in said recesses, means releasably securing said locking ring to said circular support, and means releasably retaining the other ends of said inner bars in the other circular support.

9. A reducing unit for treating paper stock, comprising a shell forming a treatment chamber, circularly arranged and spaced outer reducing bars carried by said shell, a rotatable shaft having a free end projecting within said outer bars, a rotor mounted on said free end of said shaft and having circularly arranged and spaced inner reducing bars concentrically disposed within said outer reducing bars, said outer and inner bars respectively having working faces in coacting stock-treating relation to each other, said shaft having its free end reduced in diameter and providing a shoulder spaced from the extreme end thereof, said extreme end of the shaft being screw threaded, said rotor having a central bore therethrough and fitting on the free end of said shaft and also having a portion in engagement with said shoulder on the shaft, and a breaker head comprising a central hub and radially projecting breaker arms on said hub, said hub having a screw threaded recess in one end thereof and being engaged with the threaded end of said shaft, with the rotor clamped between said breaker head and the shoulder on said shaft.

10. A reducing unit for treating paper stock, comprising a shell forming a treatment chamber, circularly arranged and spaced outer reducing bars carried by said shell and diverging towards one side of said shell, supporting means disposed adjacent to said shell, a rotatable and axially shiftable shaft journalled in said supporting means, a rotor carried by said shaft and located concentrically within said outer reducing bars, circularly arranged and spaced inner reducing bars carried by said rotor, said inner reducing bars diverging toward said supporting means and being disposed parallel to said outer reducing bars in coacting stock-treating relation thereto, a thrust bearing assembly fixed on said shaft, a relatively stationary screw-threaded member rotatably mounted on said supporting means, an arm connected to said thrust bearing assembly and projecting therefrom towards said screw-threaded member, said arm having means engaged with the screw threads of said screw-threaded member, and means for rotating said screw-threaded member for axially shifting the shaft aforesaid so as to vary the stock-treating relation of the work- 11 ing faces of the outer and irmer reducing bars Number aforesaid. 2,055,143 2,182,391 References Cited. in the file of this patent UNITED STATES PATENTS 2,660,934 Number Name Date 537,260 Zimmerman Apr. 9, 1895 1,835,984 Haskell Dec. 8, 1931 Number 1,985,569 Haskell et a1. Dec. 25, 1934 10 ,9 2,047,595 Richter July 14, 1936 ,59

Name Date Bond Sept. 22, 1936 Skolnik Dec. 5, 1939 Bidwell Dec. 14, 1948 Cawooci Feb. 15, 1949 Laviste Dec. 1, 1953 FOREIGN PATENTS Country Date Great Britain of 1903 Germany Oct. 25, 1921 

